As a submissive male, I pride myself on my ability to please a woman orally; both in front and in back :)
Karen loves having her ass licked as much as any woman I've ever met. They all love it, even though at first some might seem a little hesitant/squeamish at first (I think it's just an act) but eventually they give in. Then after a couple of times they beg for it. If they know what they're doing, the demand it.
You can tell by a woman's reactions, the sounds she makes, body movements, etc. whether she's enjoying the ass licking or not. Karen's signals can't be mistaken.
One other thing she loves about regular ass worship is that it keeps her bottom hole so nice and clean, almost pristine.